dial9_trace_format/
lib.rs

1//! # dial9-trace-format
2//!
3//! A compact binary trace format for recording timestamped events with
4//! schema-driven encoding. Events are described by schemas (registered at
5//! write time) and encoded with delta-compressed timestamps, LEB128 varints,
6//! and an interned string pool.
7//!
8//! ## Crate layout
9//!
10//! - [`encoder`] — high-level [`Encoder`](encoder::Encoder) for writing traces
11//! - [`decoder`] — streaming [`Decoder`](decoder::Decoder) for reading traces
12//! - [`codec`]   — wire-format types ([`WireTypeId`](codec::WireTypeId),
13//!   [`PoolEntry`](codec::PoolEntry)) that appear in decoded frames
14//! - [`schema`]  — [`SchemaEntry`] and
15//!   [`FieldDef`] describing event layouts
16//! - [`types`]   — field value types, the [`TraceField`]
17//!   trait, and the [`EventEncoder`] used by derived code
18
19pub mod codec;
20#[cfg(feature = "serde-deserialize")]
21pub mod de;
22pub mod decoder;
23pub mod encoder;
24pub(crate) mod leb128;
25pub mod schema;
26pub mod types;
27
28#[cfg(feature = "serde-deserialize")]
29pub use de::DeserError;
30pub use dial9_trace_format_derive::TraceEvent;
31pub use types::DynamicListRef;
32pub use types::DynamicMapRef;
33pub use types::EventEncoder;
34pub use types::FieldValue;
35pub use types::InternedStackFrames;
36pub use types::InternedString;
37pub use types::StackFrames;
38pub use types::TraceField;
39
40use schema::{FieldDef, SchemaEntry};
41use types::FieldValueRef;
42
43/// Trait implemented by `#[derive(TraceEvent)]` for compile-time event types.
44pub trait TraceEvent {
45    /// Decoded form of this event, potentially borrowing from the input buffer.
46    type Ref<'a>;
47
48    /// The event type name (used in schema registration).
49    fn event_name() -> &'static str;
50    /// Field definitions for schema registration.
51    /// When `has_timestamp()` is true, the timestamp is NOT included here —
52    /// it is encoded in the event frame header.
53    fn field_defs() -> Vec<FieldDef>;
54    /// Whether this event type carries a packed timestamp in the event header.
55    fn has_timestamp() -> bool {
56        true
57    }
58    /// Return the event's timestamp in nanoseconds.
59    fn timestamp(&self) -> u64;
60    /// Encode this event's non-timestamp fields into the encoder.
61    fn encode_fields<W: std::io::Write>(
62        &self,
63        enc: &mut types::EventEncoder<'_, W>,
64    ) -> std::io::Result<()>;
65    /// Decode from field values using field definitions for name resolution.
66    /// `timestamp_ns` is the absolute timestamp from the event header (if present).
67    fn decode<'a>(
68        timestamp_ns: Option<u64>,
69        fields: &[FieldValueRef<'a>],
70        field_defs: &[FieldDef],
71    ) -> Option<Self::Ref<'a>>;
72
73    /// Build a SchemaEntry for this event type.
74    fn schema_entry() -> SchemaEntry {
75        SchemaEntry {
76            name: Self::event_name().to_string(),
77            has_timestamp: Self::has_timestamp(),
78            fields: Self::field_defs(),
79            annotations: Vec::new(),
80        }
81    }
82}
dial9_trace_format/lib.rs

dial9_trace_format/
lib.rs
